Abstract: Methods and materials for preparing specific binding reagents with a multiplicity of relatively noninterfering label moieties are described. By spacing the labels at the surface of a specific reagent with bulking agent, increased sensitivity can be achieved without interference between individual labeling entities.

Abstract: An improvement in an assay method which relies on the detection of a labeled, solubilized specific binding complex is achieved by linking the label to a component of the complex through a bond cleavable under conditions compatible with the assay and with the complex in solution.

Abstract: A thermosensitive recording material comprises a support member, (b) a thermosensitive coloring layer formed on the support member, comprising a binder agent, a colorless or light-colored leuco dye and a color developer capable of inducing color formation is the leuco dye upon application of heat thereto, and (c) a protective layer formed on the thermosensitive coloring layer, comprising a binder agent, a filler and an ultraviolet-ray-absorbing benzotriazole derivative.

Abstract: Competitive immunofluorescence assays for antigens in which immune complexes are precipitated with a nonfluorescent, nonlight-scattering precipitant such as polyethylene glycol and the resulting immunoprecipitate is dissolved with a nonfluorescent solvent of low ionic strength that maintains the pH of the solution substantially constant for immunofluorescence intensity reading. The assays are carried out by incubating the sample with fluorescent-labeled antigen, anti-antigen antibody, and a secondary antibody to the anti-antigen antibody followed by addition of the precipitant to form an immunoprecipitate. The precipitate is separated by centrifuging, dissolved in the solvent, and the immunofluorescence intensity of the solution is read with a fluorometer and compared to a standard curve.

Abstract: An improved method for the fluorometric measurement of a fluorescent label on a solid support surface in which the surface is read while coated with a continuous aqueous layer. For reading in a horizontal position, the surface is coated by immersion into a contained aqueous solution, and removed and read prior to evaporation to discontinuity. For reading in a vertical position, a layer of humectant is deposited on the surface to retain the water content.

Abstract: A method for quantitation of antigens or antibodies from a liquid sample on a solid surface. The sample is first sorbed directly to a nonimmunological surface. Then the surface is exposed to antibody or antigen labelled preferably with a fluorogen, to cause an immunological reaction to occur. After removal of unreacted reagent from the surface, the quantity of reacted labelled reagent is determined, as for example, fluorogen by a fluorometer. When the sample includes significant quantities of protein other than the antigen or antibody to be quantitated, buffer protein unreactive with the labelled antigen or antibody is added in concentrations sufficient to minimize the dependence of sorbed antigen or antibody upon variations in the concentration of such other protein.